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7

It is a good question, it is a gemstone hiding in the mud. I have searched the Cambridge database, all the bis-acetylacetonatonickel complexes which have four coordinate nickel centres are square planar. There are three common coordination geometries for nickel(II) which we need to consider. Tetrahedral, square plannar and octahedral. Here is a diagram (...


1

From a structure diagram alone it is hard to determine these interactions. The reason for this is that important structural parameters are stretched or shortened in order to flatten the molecule for a 2D drawing. In a first order approximation a molecular modelling kit based on balls and sticks could already be very helpful. It'll let you approximate the 3D ...


0

You may simply say that energy is needed to break a bond. Breaking a bond is endothermic. So the inverse is exothermic. Energy is released when a bond is formed. Apparently you want to just discuss what is happening when an electron approaches a proton from far away (x1 in your drawing) to a shorter distance (x2). The electron is supposed to have no ...


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The Hamiltonian for the collection of charged particles (electrons and nuclei) comprising a pair of molecules or ions has terms describing the kinetic energy of individual particles and pair-potential terms describing Coulombic interactions, that is, all interactions between particles are Coulombic. Where a Pauli repulsion term can crop up is when ...


3

I found a nice figure and the relevant statement in a paper by Frenking and Krapp (Unicorns in the world of chemical bonding models, 2006, https://doi.org/10.1002/jcc.20543): The crucial term which is responsible for repulsive interactions in chemical bonds except in two‐electron systems such as H2 is the Pauli repulsion. The three terms (a) ...


1

Lattice energy Now, according to wikipedia, NaCl has a lattice energy of −756 kJ/mol. First, we have to understand the term lattice energy. Here is the textbook explanation (Fleming: Physical Chemistry): The lattice energy is the energy required to separate the ions in an ionic lattice so that they are at infinite distance (but still ions). This would be ...


2

As you are probably aware, generalizations like "$\ce{BCl3}$ is a stronger Lewis acid than $\ce{AlCl3}$" can be problematic, as the results can be dependent on the base used and the conditions (eg solvent choice). That said, a common context for this ranking is with respect to carbonyl bases, such as in a Friedel-Crafts acylation. For these bases, $\ce{...


0

I can't give you a definitive answer, since I've not studied this myself, but here is what my physical intiution says: Let's use the following labels: Oxygen atom in the same molecule as the hydrogen: O' Oxygen atom with which the H is hydrogen bonding, i.e., the oxygen on the other molecule: O As you know, a hydrogen bond forms because of the ...


0

It has direct mechanical analogy. If you pull a tree branch weakly, it remains more or less in its original direction. If you pull it strongly, it points towards you. By other words, if an object is pulled by 2 non colinear forces, it has tendency to move itself to make them colinear, as the net force makes it to do so. If one of forces is much weaker, ...


0

The number of complex compounds that are surrounded by water molecules is quite big , a few examples of water being a ligand include [Cu(H2O)4]2+ or [Co(H2O)6]2+. Anyway oxygen is indeed less eager to donate its electrons because its electronegativity is considerably high, nitrogen for example works better as a ligand (actually the first complex compounds to ...


4

Oxygen very much does form bonds in which both electrons come from the oxygen atom. Examples include: 1. The $\ce{H3O^+}$ ion at the center of the solvated proton in aqueous acids, also available as salts of some of the strongest acids such as $\ce{(H3O)(ClO4)}$ 2. Carbon monoxide, with its triple rather than double bond. 3. Ozone, in which the oxygen ...


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Right, the text you are mentioning is not clear enough. It is not correct to say that the molecule $\ce{Al_2O_3}$ exists and is separated from the next $\ce{Al_2O_3}$. Such a molecule does not exist. A sample of $\ce{Al_2O_3}$ is made of a superposition of $\ce{Al^{3+}}$ ions and $\ce{O^{2-}}$ ions. It is not made of a superposition of molecules $\ce{...


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The quote you give clearly summarises the situation. In a solid (or liquid) there has to be some significant interaction between individual molecules otherwise there would only be gasses. This inter-molecular interaction is not that forming chemical bonds, i.e. a solid is not a super big molecule, but is additional to these and is due to the nature of the ...


-1

It is because of the higher electronegativities of Br and Cl, than Hydrogen. So there is a higher repulsion of the bonding electrons.


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The larger angles can simply be explained as a result of repulsion between the larger atoms of $\ce{Br}$ and $\ce{Cl}$. Hydrogen atoms in $\ce{PH3},$ as the are so small, experience less repulsion as compared to $\ce{Br}$ atoms in $\ce{PBr3}$ or $\ce{Cl}$ atoms in $\ce{PCl3},$ therefore the larger bond angles in $\ce{PBr3}$ and $\ce{PCl3}.$


1

Generalisations are impossible. There are many examples of strong and weak bonds in both ionic and covalent compounds There are a number of problems with the question. One is that there bonding is not an either/or concept: there is a something of a continuum between "pure" ionic and "pure" covalent bonding. There is also a lot of confusion about what sort ...


1

Part of the reason for many answers is that "stronger" can be different things. If we consider a typical two-electron bond between two atoms A and B, it can break in three ways: 1) 1 electron can stay with A and one with B: $\ce{A-B -> A. + B.}$ This is called homolytic bond cleavage. 2) Both electrons can stay with A: $\ce{A-B -> A- + B+}$ This is ...


0

Usually ionic bonds are stronger than covalent bonds. But there are exceptions. Quartz SiO2 for example is made of covalent bonds, and it melts at very high temperature (> 1400°C). I am afraid there are no general rules.


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Covalent bond is defined as the sharing of electrons between two atoms (non metals). Ionic bond is defined as the transfer of electrons from the valence shell of anion(s) to the valence shell of cation(s). On a covalent bond, there are two types of forces that held the atoms together; (1) intramolecular forces and (2) intermolecular forces. Intermolecular ...


0

Good question! Hydrogen bonding in the solid appears to be at least partially responsible for the planar (sp2) structure. ("Crystalline boric acid consists of layers of B(OH)3 molecules held together by hydrogen bonds of length 272 pm." https://en.wikipedia.org/wiki/Boric_acid) If the empty orbital on boron (which is partially filled by donation from the ...


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